Radar Summary Chart

(A 20 minute rant on THE most useless way of accessing radar data)

byDr. Bradley Muller

The Radar Summary chart—an outmoded way of looking at radar data.

• It is a computer-generated mosaic of radar echo intensity contours based on the Radar Weather Reports (SD/ROB) text product.

• Produced hourly showing precipitation types, cell movements, maximum echo tops, locations of line echoes and remarks (p. 5-50, Aviation Weather Services).

• The Radar Weather Reports (SD/ROB) product is described on p. 3-45 of Aviation Weather Services.

The bad news: no human intervention!

• **Here is what the government publication, Aviation Weather Services has to say about the Radar Weather Reports product: "This is a textual product derived from the WSR-88D NEXRAD radar without human intervention. The resolution of this textual product is very coarse, up to 80 minutes old, and should only be used if no other radar information is unavailable. [emphasis added]"**

• By extension, I would say that the radar summary chart should only be used in the absence of other, better radar information.

• **However, the FAA still tests you on the radar summary chart, which is derived from this product!!**

Radar Summary Chart

Issued hourly

Provides echo tops, echo strength, and cell movement

Radar Summary ChartNE = No echo

NA = Not available – big difference!

OM = Out for Maintenance

1st Contour – Level 1-2 radar return

2nd Contour – Level 3-4 radar return

3rd Contour – Level >5 radar return

R = Rain

RW = Rain Showers

TRW = Thunderstorms/rain showers

Underlined numbers – echo tops (100s of feet)

Arrows/numbers –direction and speed (kts)

Radar Summary Chart

Radar Coded Message

Similar to Radar Summary but color-coded and updated half-hourly

Numbers indicate echo tops, wind barbs represent cell movement

Why I hate the Radar

Summary Chart—and you should too!

Ground clutter and terrain—not precip.!

• Mosher’s “Day/Night Vis” at 1400z: Fog/stratus/DZ along coast.• Snow, a few Cu in the mountains.• Sacramento Valley: No clouds and no precipitation!

GOES IR Image—no rainclouds over AZ or CA!

Radar Coded Messages for same time shows no precip. in CA and AZ.

But wait…it gets worse…

Thunderstorms in the Sothern California desert?

Yuma, AZ radar.

Hanford, CA radar.

Edwards Air Force Base radar.

GOES VIS Satellite 1530z.

• “No human intervention” leads to thundershowers with 39,000 ft tops being reported based on ground clutter and anomalous propagation!

• That’s why I hate the Radar Summary Chart—and you should too!!